Attme



CHARLES EDQUARD GUILLAUME, 0F SEVRES, FRANCE.

COMPENSATING BALANCE-SPRING FOR CHRONOMETERS AND WATCHES.

No Drawing.

To all whom it may concern:

Be it known that '1, CHARLES EDOUARD GUILLAUME, a citizen of the Swiss Republic, and resident of Sevres, Seine-et-O-ise, France, have invented new and useful Improvements in Compensating Balance- Springs for Chronometers and \Vatches, of which the following is a full, clear, and exact specification.

This invention relates to improvements in compensating balance springs for chronometers and watches.

Compensation in watches for variations in temperature is effected either by the balance or by the balanceor hair-spring. The latter method possesses, as compared with the former, the advantage of being simple and consequently of being of small cost, but it has hitherto always been incomplete. It is based upon the employment of a spring made from an alloy of iron and nickel, the modulus of elasticity of which increases with the temperature within the limits of temperature in which compensation is required; it has even been proposed to employ alloys the modulus of elasticity of which decreases less rapidly than that of steel, in order to thus obtain a partial compensation. In this connection reference is made to U. S. Letters Patent Perret No. 669763, dated March 12, 190-1, appli- .cants U. S. Letters Patent Nos. 1106206 and 1106207, dated August 4., 1914., and

S wiss Patent No. 15527, dated April 21, 1898. In no one case has the compensation obtained been complete as there remains in the movement of the parts regulated, what is known as a secondary error which is of recognizable importance in the .sense that if, for example, a watch fitted with such a spring has the same rate of movementat 0 and 30 C. it gains from 20 to 25 seconds per day at 15 and loses at temperatures outside the limits of 0 and 30:. moreover, possess another important defect,

. not from the point of view of their employment but of their manufacture, that is to say, the properties of the alloy used vary rapidly with its relative proportlons of iron and nickel as also with the mode of heat Specification of Letters Patent.

These springs,

Patented Aug. 19, 1919.

I Application filed April 30, 1919. Serial No. 293,881.

treatment, so that in practice it is necessary to reject a considerable number of castings or tappings.

The alloys of iron and nickel employed in the earliest manufacture of compensating balance springs were practically pure of any addition and only contained very feeble quantities of manganese, silicon and carbon. Later there were added larger quantities of hardening substances suitable for raising the limit of elasticity, such, for example, as chromium, tungsten, vanadium, etc., but always in proportions not exceeding those ordinarily employed in metallurgy, that is to say, from 0.2 t0 4: per cent., see for example U. S. Patents Nos. 1106206 and 1106207.

Now, this invention is based upon the observation that by incorporating with the ferro-nickels large admixtures (generally comprised between 10 to 20 per cent. of their weight) of other metals capable of forming with the said ferro-nickels alloys in all pro-' portions, there are obtained new alloys which, when utilized for the manufacture of balance springs present the two following advantages, viz.

1. Not only of insuring the ordinary compensation but also of permitting a considerable diminution in, or even the complete obviation of, the secondary error, a result which has never yet been obtained by means of the balance spring.

2. Of obtaining springs which are considerably less influence as regards their elastic properties, either by small diiferences in their content -of iron and nickel, or by the heat treatment to which the metal is subjected during the course of manufacture, whereby rejections, so frequent with existing alloys, are almost entirely obviated. By this means a double technical advance is arrived at.

For ferro-nickels containing from 25 to 45% of nickel the large additions above stated may for example, be composed of chromium, copper or manganese or of two of these metals or of the three said metals simultaneously. These large additions do not alter or practically do not alter the additions of small quantities of substances having the property of raising the limit of elasticity referred to in the specifications" of the prior patents above enumerated, such, for example, as tungsten, carbon and vanadium.

From the preceding observations it will be understood that the invention which forms the subject of the present application consists of a compensating balance spring for chronometers and watches which corrects the secondary error when it is employed with a continuous or unsplit balance wheel and is formed from an alloy of iron and nickel which contains a minimum of 25% and a maximum of 45% of nickel together with large quantities varying from 10 to 20 per cent. of at least one of the series of metals, such as chromium, copper and manganese which are capable of forming with the ferronickels alloys in all proportions. The limit of elasticity of the alloys employed for the balance springs may be increased by small additions (0.2 to 4 per cent.) of bodies such as vanadium, tungsten and carbon.

As an example, the spring may be composed of an alloy, the composition of which is comprised between the following limits.-

Iron 44 to53 parts. Nickel 33 39 Chromium l0 l2 Tungsten 1 2 Carbon 0.5 1 Manganese and silicon together 1 F 2 The variations in the proportions indicated in this example although not limitative show nevertheless that a compensating balance, spring with a secondary error, which is m'Z or very small, may be obtained within large limits as regards the composition of the alloys employed for the spring, provided this composition complies'with the principle herein set forth.

What I claim is: I

1. A compensating balance spring for chronometers and Watches which practically eliminates the secondary error when employed with a continuous balance and composed of an alloy of iron and nickel (the latter in the proportion of from 25 to 45 per cent.) containing from 10 to 20 per cent.

of at least one metal capable of alloying in all proportions with the ferro-nickels.

2. A compensating balance spring for chronometers and watches which practically eliminates the secondary error when em-' ployed with a continuous balance and composed of an alloy of iron'and nickel (the latter in the proportion of from 25 to 45 per cent.) containing from 10 to 20 per cent. of chromium.

3. A compensating balance spring for chronometers and watches which practically eliminates the secondary error when employed with a continuous balance and composed of an alloy of iron and nickel (the latter in the proportion of from 25 to 45 per cent.) containing from 10 to 20 per cent. of manganese.

5. A compensating balance spring for chronometers and watches which practically eliminates the secondary error when employed with a continuous balance and composed of an alloy of iron and nickel (the latter in the proportion of from 25 to 45 per cent.) containing from 10 to 20 per cent. of chromium and copper.

6. A compensating balance spring for chronometers and watches which practically eliminates the secondary errorwhen employed with a continuous balance and composed of an alloy of iron and nickel (the latter in the proportion of from 25 to 45 per cent.) containing from 10 to 20 per cent. of chromium and manganese.

7. A compensating balance sprin chronometers and watches which practically eliminates the secondary error when employed with a continuous balance and composed of an alloy of iron and nickel (the latter in the proportion of from 25 to 45 per cent.) containing from 10 to 20 per cent. of copper and manganese.

for

8. A compensating balance spring for chronometers and watches which practically eliminates the secondary error when em- .ployed witha continuous balance and comployed with a continuous balance and composed of an alloy of iron and nickel (the latter in the proportion of from 25 to 45 per cent.) containing from 10 to 20 per cent. of at least one metal capable of alloying in all proportions with the ferro-nickels and from 0.2 to 4 per cent. of at least one other body .'capable of raising the limit of elasticity.

10. A compensating balance sprin for chronometers and watches which practically eliminates the secondary error when employed with a continuous balance and coinposed of an alloy of iron and nickel (the latter in the proportionof from 25 to 45 per cent.) containing from 10 to 20 per cent. of

at least one metal capable of alloying in all proportions with the ferro-nickels, 1 to 2 per cent. of tungsten, 0.5 to 1 per cent. of carbon and 1 to '2 per cent. of manganese and silicon (taken together).

11. A compensating balance spring composed of an alloy consisting of from 44 to 53 parts of iron, 33 to 39 parts of nickel. 10 to 12 parts of chromium, 1 to 2 parts of tungsten, 0.5 to 1 part of carbon and 1 t0 2 parts of manganese and silicon (taken together).

In Witness whereof I have hereunto signed my name this third day of April, 1919.

CHARLES EDOUARD GUILLAUME. 

